To transmit information with fixed rate under the environment of deep space communication, the communication quality and system efficiency will be affected. When the channel quality changes during the communication, adjusting the transmission parameters of the communication system in real time can guarantee the performance indexes of the system such as bit error rate(BER) meet the requirements, and improve the efficiency of communication system. Combining the requirements of the proximity-1 space communication protocols, a symbol rate adaptive transmission system scheme that meets the requirements of CCSDS protocol is designed by using SNR of the channel estimation as the standard for measuring the quality of the channel. The hardware implementation platform is based on Xilinx Kintex-7 FPGA chip. Experimental results show that the system can estimate SNR above 0 dB in the case of additive Gauss white noise, and adjust the symbol rate adaptively. Compared to fixed rate transmission, both BER and throughput performance of the symbol rate adaptive transmission system have been improved, which can provide a useful reference for the design of deep space communication system.